Jump to content
GMS, SMS, and WMS User Forum

Michal

Members
  • Posts

    81
  • Joined

  • Last visited

Profile Information

  • Location
    Czech Republic

Recent Profile Visitors

1,692 profile views

Michal's Achievements

Newbie

Newbie (1/14)

0

Reputation

  1. You can input rainfall as infiltraton rate FINF. UZF package should take care of calculating true groundwater recharge from this flux accordingly.
  2. Yes, you input infiltration rate (L/T) at land surface as FINF (NCOL, NROW). The documentation is here: https://water.usgs.gov/nrp/gwsoftware/modflow2000/MFDOC/index.html?uzf___unsaturated_zone_flow_pa_3.htm https://pubs.usgs.gov/tm/2006/tm6a19/pdf/tm6a19.pdf
  3. Hello, There is a parameter in the swt_v4.f on line 200 called MXPER. It should be just a matter of changing its value to lets say 100 000 and compiling.
  4. Hi Lalith, this is because you used layer range. If you use Screen Top/Bot GMS will use different algorithm and the amount specified will be total for entire well. Or you could just leave it as Layer range and set the Q value as 1/3 of the total rate (if the well is set in 3 layers). I belive this is intentional GMS feature.
  5. Hi, well, I think this feature that is not working properly. Here is an excerpt from MT3D manual, that describes how it handles units: "The MT3DMS code uses any consistent units for input and output variables. In the input file to the Basic Transport Package, the user decides the units for time, length, and mass. Then, any input variable or constant should be entered in units consistent with the three basic units. ..." [chapter 6.2 of Zheng, Wang (1998): MT3DMS A modular three-dimensional multispecies transport model for simulation of advection, dispersion and chemical reactions of contaminants in groundwater systems (Release DoD_3.50.A).] There is more in the chapter, so please read it. You can contact technical support for GMS and point them to the problem. I would treat the units specifed in GMS as purely informative for the user. I think the value for a given property you specify goes directly into the input files of MT3D. And therefore if you specify values of a mass rate in terms of different units compared to what your input concentrations are, your outputs will most likely be wrong (and cannot simply be rescaled). Also if there is any nonlinear process involved in the simulation the units must be consistent otherwise the results will be wrong.
  6. Hi, I agree it is poorly documented. I had to dig into the source codes to figure it out. It seems to be an excess infiltration volume rejected by the model. It can be routed to other packages as described in the ModelMuse documentation: "If the applied infiltration rate is larger than the vertical hydraulic conductivity, the actual infiltration will be reduced to the vertical hydraulic conductivity. Any remaining potential infiltration will be available to the MVR package as rejected infiltration." So I guess if you lower your infiltration rate this term should approach zero. I have no idea why the text description in the budget file states "HORT+DUNN". Maybe somebody else could clarify that.
  7. Hi Bruce, it is hard to tell. I suggest you to compare the HK and Sy arrays of the HDF5 and native MF version of your model. See if they are different. They should be exactly same. You could read the HDF file directly using Python for instance, see the discussion here. Good luck Michal
  8. Here is the relationship from the manual:
  9. Hi, I think what you are trying to achieve could be done only aproximately, because you only have to assume what the head in the model will be. Anyway, for a given cell Qb = cb (hb - h), where Qb is the flow into the cell from the source cb is the conductance between external source and the cell hb is the head assigned to the external source and h is the model calculated head in the reference cell You problably have measured hb, so I would calculate cb this way: cb = Qb / (hb-h) But as I said, you can only assume what the value of h will be. Maybe calibrating the model against the measured flow could be a better practice.
  10. Hi, it is actually quite simple. Each stress period is divided into one or more time steps. The time steps within a stress period does not have to be the same length, but can increase exponentialy in length in order to capture system response to change in stress more accurately. So by specifying a multiplier f, each following step is f multiple of the previous step. So if you have stress period of lets say 10 days and you want to solve it in 3 time steps with 4.0 as multiplier, modflow would calculate the following step lengths: {0.47619, 1.90476, 7.61905} It is not so hard to figure the realtion as for timesteps 0 to n: step_length_i=(perlen*f^i)/Sum[f^i, {i, 0, n - 1}]
  11. There is a trick that could be used with MODFLOW. One could think of the Z coordinate as Y and model it as single layer model. But this is off the table for SEAWAT due to gravity vector orientation.
  12. Hi, I think you could use the conceptual model approach. You need to think of your cross section model as a normal layered aquifer model, that has only a single row. Therefore everything has to be treated layer-wise. You need to follow the MODFLOW logic, there is no special case for cross section models. And you obviously need to add Y coordinate to your elevation dataset.
  13. Hi, well the message desribes the issue. There is only one point in the scatter point dataset you interpolate from. I would double check that the scatter points do not have this error.
  14. Hi Jonathan, I was dealing with similar issue some time ago. There is not a satisfying way how to do it in GMS. The solution depends on the complexity of the task, but it involves grid level approach. You can isolate cells by material, select boundary cells by intersecting with boundary Arc (from Top view, Orto off) and adding a Sink/Source term. In some situtions it may be convenient to map BC form conceptual model to all layers and delete from grid where appropriate. This works if the boundaries do not overlap. Or you can modify the Package outside GMS with some script.
  15. Hi Rachel, The problem is probably that the concentration observation file is not generated after your model finishes. Therefore PEST complains that it cannot find it. The reasons for this could be many. I suggest you to study how model equivalent concentration observations are generated with VM. Alternatively, you could do it manualy with MOD2OBS program from PEST utility suit for instance. When not sure what to do, read PEST manual.
×
×
  • Create New...